This invention relates to combine harvester control, and more particularly to a system for automatically adjusting the sieve opening, concave clearance, chaffer opening, rotor speed and fan speed in response to manipulation of a keyboard by a combine operator. The invention is particularly adapted for use in axial flow combine harvesters of the type disclosed in U.S. Pat. No. 3,742,686, but is readily adaptable for use in other types of combines.
In recent years considerable effort has been directed toward making the working conditions of a combine harvester operator more comfortable. The cab or operator's compartment has been glass enclosed to shut out noise and dirt, and to permit the cab to be air conditioned. For the enjoyment of the operator, radios and tape decks are offered as optional equipment. While these improvements have made the work of the operator more comfortable, they interfere with the traditional method of combine harvester adjustment where the operator, by manually operating controls in the cab, adjusted various operating parameters after visually observing and "listening" to the combine harvester operation.
Even where the traditional method of combine harvester adjustment can be employed unhampered, it is at best based on the expertise of the operator who must judge, from what he sees and hears, what parameters require adjustment, and how much adjustment is required. Thus, at any given time it is a matter of guesswork or considerable experience as to whether the cleaning sieve opening, chaffer sieve opening, concave clearance, rotor speed and fan speed are all correctly set for maximum yield for the particular crop being harvested and the crop moisture level.